2 tablespoons unsalted butter

1 tablespoon olive oil

2 large yellow onions thinly sliced

1 teaspoon sugar

1/2 teaspoon salt

3 garlic cloves minced

1 1/2 cups orzo pasta

2 cups cooked shredded chicken

1/2 teaspoon dried thyme

1/4 teaspoon black pepper

2 cups low-sodium chicken broth

1 cup heavy cream

1 1/2 cups shredded mozzarella

1/2 cup grated Parmesan

Optional: 1/2 teaspoon Worcestershire sauce